Method of forming curved channel members, elbows, and u-bends



J. J. SMITH METHOD OF FORMING CURVED CHANNEL MEMBERS, ELBOWS, AND U-BENDS Filed Mayi2, 1941 2 Sheets-Sheet 1 v INVENTOR, J .5211 172,

-. (Ii m6 v A'ITORN Dec.7,1943. J, J. 5m 2,335,887

METHOD OF FORMING CURVED CHANNEL MEMBERS, ELBOWS, AND U-BENDS- Filed May 2,1941 7 2 sheets-sheet 2- INVENTOR J. J. Smifl;

TORNl-ZY Patented Dec. 7, 1943 UNITED STATE S "PAT ENT OFFICE METHOD OF FORMING CURVED CHANNEL MEMBERS, ELBOWS, U-BENDS James J. Smith, Philadelphia, Pa. Application May 2, 1941, Serial No. 391,578 4 Claims. '(Cl. 29-157) (Granted under the act of March 3, 1883, as

amended April 30, 1928; 370 O. G. 757) it possible to form from metal plates of any thickness articles of this nature,'whlch heretofore have hadto be made of cast metal, it being understood that the term bend is the termheretofore used, to describe the resulting article by the method by which it was formed, whereas a so-called bend'? by the improved method is not, accurately speaking, a bend, but like the older form of th article is a curved section, of 45 degrees, 90 degrees, 180 degrees, etc.

More particularly, the object of the present .invention isto provide an improved method of making a curved section of channel member, pipe or tubing from metal plates by a different series of steps than those heretofore employed, and in which the thickness of the metal in the resulting articl is the same at all points, as for instance in the radially outer and the radially inner portions of the curve, as well asat points intermediate thereof. a

With the objects of the invention thus broadly stated, the detailed steps comprising the invention are hereinafter fully brought out in the following description, when read in conjunction with the accompanying drawings in which;

Figs. 1 and 2 are plan views ofmetal plate blanks from which half portions of 90 and 180 degree sections are to be formed;

Fig. 3 is a section on the lines 3-3 of each of. Figs. 1 and 2; v

Fig. 4 is a top plan view of the concavely 'channeled die and forming roller in operative relaroller and die have formed the interpositioned blank;

Fig. 7 is a plan view showing two curved sections oppositely positioned with respect to each other, but before being integrally united;

Fig. 8 is a similar view after being united to form a curved pipe section;

Fig. 9 is a plan view of an annular flange;

, Fig. 10 is a plan view of the curved pipe section terminal of Fig. 8 after two of the terminal flanges hav v also been secured integrallythereon; Y

Fig. 11 is a plan view of a completed blank still in the forming die, which blank has a degree curved channel portion with straight sections at its ends;

Fig. 12 is a section on line |2l2 of Fig. 11 showing the plane straight end portions .of Fig. 11; I I

Fig. 13 is a sectional view showing the channeled curved portion on line l3l3 of Fig. 11; and

Fig. 14 is a cross sectional view of various shapes that have been formed according to this invention.

' Referring to the drawings, there is illustrated in Fig. 1 an arcuate metal plate or equivalent blank I of 90 curvature, and in Fig. 2 a annilar blank 2 of18.0 curvature,--the transverse shape of these blanks being indicated by Fig. 3. It is to be borne in mind that the 90 and 180 curvatures represented by Figs. 1 and 2 are merely illustrative of any curvature, which may be necessary to provide for the formation of a channel member or curved pipe section such as is usually v referred-to as an elbow, U-bend, or similarly,.it

being understood that a pair ofduplicate blanks are provided for each such curved pipe section.

Referring to Figs. 4, 5, and 6, there is shown a forming die 3 of any desired cross section, except that it is definitely provided with a curved recess or trough 4, which inthis figure is shown as being semi-circular in cross section and in plan is of the same curvature, whether regular or irregular, as that of the finished channel member or pipe section, it also being understood that chan-' nel members orpipe sections having the shapes similar to or suggestive of a- 0, J, 0, S, or the like may be formed, as well as L's and U-bends, above referred to. In any such case, a roller 5 is mounted upon a suitable shaft or other support 6, and by any suitable apparatus (not shown) is guided through a path parallel with the center line of the said trough or concave recess in the forming die. The shape and size of said roller is such that it corresponds with the transverse shape of said trough or recess, but is sufficientlysmaller than-the latter to provide for the rolling and interpositioning of one of said blanks therebetween, as shown in Fig. 6, it being further understood at this point that the present method anticipates the formation of curved channel members or pipe sections having channel; elliptical, ovoid and similar cross sections, other than circular.

In carrying out the present method, a blank is first laid upon the preferably, though not necessarily, planular upper surface 1 of the forming die 3, after which said die and rollerare moved relative to each other, with the roller in the upright position shown in Fig. 5, while gradually increasing pressure is applied to said roller, to thereby force said blank into the trough or recess 4, until it accurately conforms to the transverse shape of the latter, as shown in Fig. 6. If a pipe is being made, after forming a pair of such semi-tubular sections 8 and '9, they are placed in parallel relation with each other, as shown in Fig. 7, then brought together and welded along the line of their adjacent edge surfaces I0, to provide a pair of integral reinforced seams I l, as shown in Fig. 8'.

As it is difficult in practice to so shape the original blank, that its edges when removed from the forming die will be absolutely smooth and lie in the same plane, it has been found advisable to grind the said edges so as to provide planular surfaces, after the semi-tubular section has been removed fromsaid forming die.

Having completed a curved pipe section,- provision for connecting the ends of the same to other sections of straight or ,curved pipe is made by integrally securing, as by welding, an annular flange l2 upon and about either or both of the ends of the curved section, as shown in Fig. 10, said flanges, if desired, being provided with apertures or other form of cutout regions, for connecting together pairs of them upon adjacent pipe sections by any suitable fastening means, such as bolts, clamps, or the like.

In Fig. 11 the method of this invention is shown as forming a channel portion in a curved segment of a plane blank. As shown at 13 in Fig. 12,- the entire blank is originally in the same plane and includes a curved center portion I4 of 90 degrees radius and having straightend portions I and I6. As applied to this form, the blank I3 is placed with its curved center portion l 4 over the curved forming die I! and then rolled into this die I! by a roller of appropriate shape but otherwise identical in operation'and construction with the roller 5 to provide the channel portion H as shown in Fig. 13. Obviously, plane end sections l5 and [6 may be omitted, in which case'the channel shaped portion l4 would end at the ends of the die l1. Likewise it is conteme plated that the straight sections and 16 could be formed into a channel section similar to the curved channel section 14 by merely providing an appropriately shaped die and passing the roller along such straight portions of the die l1.

Although, as shown in Figs. 1 to 6, the transverse shape of the completed curve member is circular in cross section and, as shown in Fi 13,

the transverse shape is channeled shaped in the of suchcross sections successfully completed by this invention are shown generally in Fig. 14, at

20 to 38 inclusive.

Tests have proved or established the fact, that curved channel members or pipe sections formed by this improved method are entirely free from cracks resulting from stretching, or crimps resulting from forced contraction, and are also entirely free from any portions of either thicker or thinner dimensions than that of the original blank, by'contrast with tubes or channel members .which are curved to provide curved channel members, elbows, U-bends, and the like, and in which case the radially center portions are thinner, due to stretching and the radially inner portions are thicker and often show crimps, due to compression about a curved surface or guide. Thus, the product of the present improved method is characterized not only by uniform thickness, but also uniform internal tensions or stresses.

It should be borne in mind that the present method involves the important and unprecedented principle which consists in rolling the metal of the blank plate two ways simultaneously, that is, vertically or at right angles with respect to the plane of the die and also angularly about the center or axis of the groove or trough within the die. It is generally considered by experts in the art that such treatment of metal is both impracticable and impossible of accomplishment.

In interpreting the appended claims, it is to be understood that the particular form of the device hereinbefore described, and illustrated in the accompanying drawings, is merely illustrative of some embodiments of the invention, and that said invention is capable of being modified in many ways, as to the exact details of its construction and operation, without departing from the scope of the appended claims.

The invention herein described and claimed may be used and manufactured by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

What is claimed is:

1. The method of forming a curved pipe section, which consists in providing a pair of flat plate blanks defined transversely by a pair of substantially concentric edges, the medial radius of each blank being substantially the same as that of the finished pipe section, progressively rolling said blanks along an are having said medial radius by gradually increasing pressure into a trough-shape to cause both a transverse and a longitudinal flow of metal, thereby producing a uniform wall thickness, and then integrally uniting the corresponding edges of said sections.

2. The method of forming a'curved pipe section, which consists in providing a pair of fiat segmental plate blanks having medial radii the same as that of the finished section, progressively rolling said blanks into the longitudinally curved concave trough of a forming die, which is transversely equal to substantially one-half of the cross-section of the finished pipe section, to form complementary, semi-cylindrical longitudinally curved pipe sections, the radius of said trough being also the same as that of the finished pipe section, and then integrally uniting said blanks along their corresponding edges.

3. The method of forming the curved portion of a sheet metal member into a channel curved about an arc of a circle which consists in providing a flat plate metal blank having a curved portion defined transversely by a pair of substantially concentric circular edges and having a medial radius substantially the same as that of the finished channel, rolling the said blank along a circular are having the said medial radius to bend only the medial portion or the blank into the desired concave cross sections, continuing the rolling along the said arc with increased pres sure to progressively bend the said blank on each 5 side of the first formed portion tothe desired shape, and finally rolling along said are the progressively bent blank throughout its radial extent at the same time and throughout its extent in the direction of rolling to provide a uniform 10 curvature.

4. The method or forming the curved portion at a sheetv metal member into a channel curved about an arc of a circle which consists in providing a flat plate metal blank having a curved por- 1 6 assess? 3 tion defined transversely by a pair of substantially concentric circular edges and having a mea dial radius substantially the same as that of the finished channel, rolling the said blank along a circular are having the said medial radius to bend only the medial portion of the blank into the desired cross sections, continuing the rolling along the said arc with increased pressure to progressively bend the said blank on each side 

